Inverse Opal CuCrO Photocathodes for H Production Using Organic Dyes and a Molecular Ni Catalyst.

Dye-sensitized photoelectrochemical (DSPEC) cells are an emerging approach to producing solar fuels. The recent development of delafossite CuCrO as a p-type semiconductor has enabled H generation through the coassembly of catalyst and dye components. Here, we present a CuCrO electrode based on a high-surface-area inverse opal (IO) architecture with benchmark performance in DSPEC H generation. Coimmobilization of a phosphonated diketopyrrolopyrrole () or perylene monoimide () dye with a phosphonated molecular Ni catalyst () demonstrates the ability of IO-CuCrO to photogenerate H. A positive photocurrent onset potential of approximately +0.8 V vs RHE was achieved with these photocathodes. The -based photoelectrodes delivered photocurrents of -18 μA cm and generated 160 ± 24 nmol of H cm, whereas the -based photocathodes displayed higher photocurrents of -25 μA cm and produced 215 ± 10 nmol of H cm at 0.0 V vs RHE over the course of 2 h under visible light illumination (100 mW cm, AM 1.5G, λ > 420 nm, 25 °C). The high performance of the PMI-constructed system is attributed to the well-suited molecular structure and photophysical properties for p-type sensitization. These precious-metal-free photocathodes highlight the benefits of using bespoke IO-CuCrO electrodes as well as the important role of the molecular dye structure in DSPEC fuel synthesis.